Method and means for connecting and telecontrolling a large number of electrodes for electrical cell stimulation in living organisms

ABSTRACT

A system for neural and muscular stimulation, including DBS, cortical and muscle stimulation, heart pacemakers and similar applications. The improvement of our invention over prior art consisting of the possibility of a larger number of electrode pads from where to originate the electrical stimulation for better control of the process. Our invention discloses a system of address wires which controls switches and demultiplexers to select one of a plurality of wires and one of a plurality of electrode pads from where the electric stimulation starts, and latches that maintain some selected choices after the address buses go on to select other wires and other electrode tips. Our invention also discloses time delay lines which are used to keep the stimulating pulses for a pre-assigned time. Finally, our invention discloses telecontrol to select the active electrodes.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/250,909 currently allowed, which is a continuation of U.S. Pat. No.8,738,135, which is a continuation of U.S. Pat. No. 8,565,868. Thisapplication is based on, and claims benefit of Provisional ApplicationSer. Nos. 61/194,515, filed Sep. 29, 2008; and 61/198,029, filed Nov. 3,2008.

FEDERALLY SPONSORED RESEARCH

Not Applicable

SEQUENCE LISTING OR PROGRAM

Not Applicable

BACKGROUND OF THE INVENTION Field of Invention

This invention relates to cellular electrical stimulation in general,for animals, including humans, and neuron electrical stimulation inparticular.

Definition of Terms

To assert. In digital electronics it means to make a wire on or off, asneeded, or a set of wires to be in any combination on and off, asneeded. In this context “on” an “off” generally mean one of the twopossibilities of a binary representation, as on=5V, off=0V, on=magneticfield up, off=magnetic field down, on=light, off=dark, etc.

B/H/D after a number, or in subindex, stands for binary/hexadecimal(hex)/decimal number representation. For example: 1010B=0AH=10D

Bus. A set of wires grouped according to its function. For example, theaddress bus is the set of wires which carries the address value forsomething, the data bus is the set of wires which carries the data, ornumerical value for something.

Demultiplexer. A type of electronic switch with a single input and aplurality of outputs, also with a number of binary inputs capable ofcreating a binary address which can select which of the outputs will beconnected to the single input (cf. multiplexer). The device of ourinvention uses a demultiplexer capable of also latching the outputselection, that is, a demultiplexer that maintain the connection betweenthe single input and the selected output even after the address is outfrom its address port (it latches), or even if the address changes toanother value.

Integrated circuit. As used herein, the term “integrated circuit” refersto a small-scale, electronic device densely packaged with more than oneintegrated, electrical component. The components are manufactured on thesurface of semiconductor material. There are various scales ofintegrated circuits that are classified based on the number ofcomponents per surface area of the semiconductor material, includingsmall-scale integration (SSI), medium-scale integration (MSI),large-scale integration (LSI), very large-scale integration (VLSI),ultra large-scale integration (ULSI)

Latch. A term used in digital electronics meaning the capability to keepsome particular configuration, or output, or logic, or selection, evenafter the selecting source, etc., is no longer active, or even if theselecting source is changed to a different value. Another way to look atit is that a latched device has memory to keep a configuration wheninstructed to do so. A standard wall light switch is an example of alatch because it keeps the last state it was set by a human being,either on or off.

Measuring tip. The very tip of the measuring wire, sometimes referred aselectrode in current art, made of metal or some other electricallyconducting material. In current art devices the measuring tip isgenerally at the end of a thin, stiff wire, typically 100 micrometersdiameter, separated by 100 micrometers, or more, while in our inventionthe measuring tip is a metallic area as small as a few micrometers,typically 5 micrometers but can be less or more according to the need,separated by as little as 5 micrometers, at the surface of the device ofour invention. Current art is capable of manufacturing measuring tipsfor our invention that are less than one micrometer in diameter, and theshape is not necessarily circular.

Multiplexer (MUX) a type of electronic switch with a plurality of inputsand one single output, also with a number of binary inputs capable ofcreating a binary address which can select which of the inputs will beconnected to the single output. (cf. Demultiplex).

Neural sensor. As used herein, the term “neural sensor” means animplantable device for sensing neural signals. Examples of neuralsensors include microwire electrode arrays, optical sensors, microwires,magnetic field detectors, chemical sensors, and other suitable neuralsensors which are known to those of skill in the art upon considerationof the present disclosure.

Picafina. A supporting structure used by the main embodiment of ourinvention, generally similar to the devices used in Deep BrainStimulation but potentially with far more tips or electrodes than DBSdevices, which is strong enough to allow it to be inserted in the brainor other body structures, and which contains the necessary wires forconnecting the measuring tips and the address decoders with thecontrolling and measuring instruments. For use in human animals, hedimension of a type I picafina is approximately the diameter of a widedrinking straw (5 mm.), its length being the necessary to reach thedesired depth in the body. For smaller animals (as a mouse), thepicafinas would be accordingly smaller, both in diameter and length,while for larger animals (as a whale or an elephant), the picafinaswould be accordingly larger.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates to cell electrical stimulators and reading probesfor animals, including humans, in general, and brain electricalstimulators and reading probes in particular.

2. Short Introduction to the Art

It is well established that the neuron signals are electricalpropagating signals. The roots of this fact can be traced at least tothe Italian Luigi Galvani as early as 1771 with his famous frog's legexperiment. Electrically stimulating neurons that carry orders tomuscles, or electrically stimulating the muscles directly, can thereforecause the muscles to contract or relax. It follows that the spinal cordand the whole brain, being as they are a collection of neurons, areelectrical devices, the function of which could be expected to beaffected if electrical currents were forced on them by some externalagent.

Focusing attention now on the brain, it has been established thatdifferent brain functions occur in different parts of it, though someparts of the brain are known to be shared by more than one function. TheFrench Paul Broca is credited with the first unequivocal evidence thatthe brain is segmented in areas with specialized functions (brainworkers say “area” for what is actually a volume, a particular threedimensional part of the brain, practice that I will follow here,occasionally calling the attention of the reader to this misuse of theword). Paul Broca proved that speech is processed and controlled at asmall area (that is, a volume) today known as the “Broca area” which islocated in the left frontal lobe. Today the parts of the brain that areassociated with speech, or with vision, or with the motion of the handor with the motion of the big toe on the left foot, an so on, are allknown; the brain is all mapped, as known in the trade. Eric R. Kandel(Kandel (2000)) gives a good overview of the current state of the artfrom the academic point-of-view.

It follows from these two facts that electrical stimulation of anyparticular area of the brain (that is, a volume) should affect thefunction that depends on this area: speech, vision, motor, etc. This wasindeed experimentally determined to be true, and eventually brainelectrical stimulators were developed to affect parts that becamedysfunctional. Brain stimulation to correct for motor disorders is themost common clinical application today, but stimulation can also causeemotions when it happens in the area that is associated with them.Similarly, stimulation of nerves that carry information from the body tobe brain can stop (or cause) pain, and electrically stimulating theheart can keep it at the correct pace, or even to restart it when ithappens to stop, as is done with pacemakers and defribilators.Electrically stimulating neurons that carry orders to muscles, orelectrically stimulating the muscles directly, can therefore cause themuscles to contract or relax. This is what is achieved with heartpacemakers and heart defibrillators. A pacemaker could, in principlework stimulating the part of the brain that starts the process (assumingit is not autonomous), but this would be more complicated thanstimulating the heart directly, so pacemakers are designed to affect theheart directly, and not the origin of the signal.

Leaving aside the mechanisms that underlie the result of electricalstimulation, which are not well known in all cases, it is possible todayto use direct electrical stimulators to modify motor malfunctions asParkinson's disease, essential tremor or epilepsy, or mood states asdepression, or complex syndromes as eating disorders. Said brainelectrical stimulation is achieved with electrodes permanently implantedin the desired part of the brain, which are connected to the necessaryelectrical power source (batteries or the like) and electronic circuitryto generate the appropriate electrical pulse. Severe diseases asParkinson's disease are now treatable and often totally or largelycurable, or at least substantially controlled, with direct electricalstimulation to the appropriate part of the brain. For Parkinson'sdisease stimulation, the device is one of a class generally known asDeep Brain Stimulators (DBS), because all the known parts of the brainthat receive electrical stimulation to counter Parkinson's disease arelocated deep inside it, as the thalamus, the subthalamic nucleus (STN),the basal ganglia, or internal globus pallidus (GPi) the internalcapsule and the nucleus accumbens. The electrical pulse for DBS is AC(alternate current) at f=˜180 Hz (or 5.56 milliseconds between pulses),each pulse lasting approximately 90 microseconds (pulsewidth). Thevoltage depends on the patient, varying from as low as 2.5 V to as highas 5 V (all values approximate, varying between patients and also withtime on the same patient). A separate class of stimulators are thesuperficial brain stimulators, known as cortical stimulators, thatstimulate the brain cortex, which could also use the invention disclosedin this patent application with appropriate adaptations, largely on thegeometry of the stimulator. There are also spinal stimulators, thatstimulate the nerves at the spinal column, and other parts of the body,generally for pain control, but also for other problems. There are heartstimulators or pacemakers and also heart defribilators. These latter,heart pacemakers and defribilators, differ much from the devicedisclosed as the main embodiment of this patent application, but thesame core principle disclosed in this invention, the method and means ofmore precisely applying the stimulation, and of shaping the electricfield, so as to guide the current, apply to them too. Anotherapplication is artificial muscle stimulation, where artificial materialscapable of contraction or distention when receiving the appropriatesignal are used as artificial muscles. Another class of devices iscomposed of measuring probes, designed to measure the voltage (orcurrent) in the brain or other body parts. All these variations canincorporate the system and method disclosed here to allow the use of avery large number of electrical contacts for stimulation or formeasurement.

3. Discussion of Prior Art

The success of DBS to ameliorate Parkinson's disease symptoms is knownin the medical community, particularly among neurosurgeons. Yet, manyforms of Parkinson's diseases and other movement disorders too, areeither unresponsive or only partially ameliorated by DBS (Okun (2006)).It is unknown the causes of the differences, but one of the speculationsis not optimal positioning of the stimulating electrode, which would, asexpected, fail to have optimal effect in this case due to failure tostimulate the chosen area. Benabid (1994) and Benabid (2001) discussthis problem and others. Additionally, the success of DBS procedures candiminish over time. This deleterious effect is discussed by M. C. Kim etal. (Kim (2002)). This latter decrease in efficacy of DBS is thought bysome neurosurgeons to arise from motion of the implant inside the braindue to occasional sudden head movements, particularly due to a fallingbut also other causes. Our invention allow for correction of thesedeleterious factors.

Known side effects from brain stimulators caused it to be recognized theneed for smaller electrode area for neural stimulation, but since nobodyhas been able to precisely position the stimulator in the brain, theonly option has been to stimulate an area that is likely to be largerthan necessary. This has been a widely known problem in the art of brainstimulators: unwanted side effects, as mood changes, uncontrolled motionof other muscles not intended to be affected, etc.

In “Detailed description”, section A-1 Andrew Firlik et al. (Firlik(2009)) states that “The method 100 includes a diagnostic procedure 102involving identifying a stimulation site at a location of the brainwhere an intended neural activity related to the neural-function ispresent.”, which indicates that these inventors are aware of the need toidentify a location of the brain where to apply stimulation. Yet theirdevice assumes that the implant is indeed positioned at the desiredtarget location, which the neurosurgeons know to be a very difficulttask. Indeed, the difficulty of this task is indicated by the acceptanceby the neurosurgeon community of the side effects, which arises fromincorrect positioning of the stimulating device, which then applieselectrical current also into undesired areas, thereby causing the knownside effects. Our device offers a great latitude of the electricalstimulation point, thereby solving this problem. Moreover, Firlik et al.disclose an innovative application of their invention, which is to useelectrical stimulation during physical therapy designed to readapt thebrain of patients that have suffered some form of brain loss, eitherfrom a stroke, a car accident or the like. Such an application wouldrequire an adjustment of the stimulation site, which is difficult toachieve with the device they disclose, while the device we disclose inour invention is more suitable for readjusting the point of applicationof the electrical stimulation.

Wiler at al. (Wyler (2009)) At the end of the background section, theinventors acknowledge that: “Because MCS involves the application ofstimulation signals to surface regions of the brain rather than deepneural structures, electrode implantation procedures for MCS aresignificantly less invasive and time consuming than those for DBS. As aresult, MCS may be a safer and simpler alternative to DBS for treatingPD symptoms. Present MCS techniques, however, fail to address oradequately consider a variety of factors that may enhance or optimizethe extent to which a patient experiences short term and/or long termrelief from PD symptoms.” Which is likely to be a consequence that theirinvention is unable to precisely adjust the point of application ofelectrical stimulation, which is exactly the solution proposed by ourinvention. It is apparent, therefore, that the need for preciselypinpointing the location of application of the electrical stimulation isknown in the art, at the same time that its solution has evadedsolution.

Anne Pianca (Pianca (2007)) discloses a DBS system that works inassociation with a separate measuring electrode which aids in thelocation of the optimal placement of the DBS device. Yet Pianca'sinvention suffers from the disadvantage of increased trauma to thepatient due to multiple insertions and withdraws of invasive instrumentsin the brain. A better solution would avoid such traumatic repetitiveinsertions. Our invention provide such improvement.

Benjamin Pless (Pless (2004)) also describes a device that reads thewaveforms produced by the brain, similarly to a EKG, and acts on thesemeasurements, under the control of a microcomputer or similar device, toinject electrical current in the brain to forestall such symptoms asepileptic seizures. Pless device again fails to teach any means toprecisely measure and to precisely insert the electrical correctivepulse.

Potential movement of the device, as well as other characteristics, arealso disclosed in another US patent by Carl Wahlstrand (Wahlstrand(2008)), but again these inventors fail to solve the problem of thenumber of electrodes and the possible number of wires to use.

Brain stimulation is known to have other effects besides motor innature. For example, R. Hu (Hu (2009)), discuss the effects of it inmemory formation. Hu's work is an indication of the possible sideeffects that may occur if the brain stimulation, intended to stimulate acertain part of it, goes beyond the intended area.

A good analysis of the pros and cons of the use of direct electricalbrain stimulation can be found in B. Kluger et al., (Kluger (2009)).

Finally, there is the problem of DBS in children, whose brains areguaranteed to change size, thereby invalidating the initial positioningof the implant. W. Marks (Marks (2009)), review the use of DBS inchildren. This is a particular interesting and valuable application ofour device because as children grow, the distal extremity of the implantslides away from its initially implanted location. With our device, withits larger number of electrodes, there exists a larger latitude ofreprogramming to continue stimulating the same area (volume) of thebrain after it slipped away due to growth.

Brain electrical stimulation is made with an electrode capable ofdelivering electric current to a chosen area (volume) of the brain.There exist two general classes of brain stimulators: cortical and deepbrain stimulators. In a later section I will describe a preferredembodiment of my invention for deep brain stimulation, and accordingly Iwill describe here a current art used for deep brain stimulation.Cortical brain stimulators, spinal (nerve) stimulators, etc., functionon substantially similar principles, as known to the people familiarwith the art, the adaptations for which are obvious to the ones familiarwith the art. Similar adaptations of the invention disclosed below arealso, mutatis mutandis, used for measurement devices, that is, forelectrodes designed to measure the electrical activity inside bodycavities, particularly at the neurons. Similar adaptations of theinvention disclosed herein are also possible for cardiac stimulators,for example. Cardiac stimulators can also improve with more preciselocation of the electrical stimulating pulses, as provided by ourinvention.

A DBS (Deep Brain Stimulator) is an electrical stimulator devicecomposed of a battery for electrical power, an electronic circuitry forelectrical pulse generation of appropriate amplitude, frequency, pulsewidth and shape, connecting wires and a wand, or lead, or picafina, fromnow on referred to as the picafina, that delivers an electrical pulse tothe brain target location. The battery and microelectronic circuitry arehoused in a hermetic sealed housing of material compatible with humantissue. This housing is typically implanted under the clavicle orsomewhere else in the chest, from where extension wires are passed underthe skin up the neck, usually behind the ear, to bring the electricalpulse from the generating box to the picafina. Alternatively theprogrammable oscillator and battery are located on the patient's skull,as disclosed by Pless et al., U.S. Pat. No. 6,810,285 (Pless (2004)), orby Janzig et al. Janzig (2003) “Low Profile Implantable Medical Device”International Application No.: PCT/US2003/038927, but the physicallocation of the electronic circuit and battery are of no importance forthe functioning of the device disclosed in this invention. For DBS, thepicafina is inserted from a burr hole on the top of the skull,vertically down, deep within the brain, to deliver the electrical pulsesat some appropriate target area. The picafina, which is the only partinside the brain, has the approximate dimension of a 3 in. long drinkingstraw: 7 cm long, 3 to 5 mm diameter. At the picafina's distal end thereare typically four metallic rings, each one individually connected by anindependent wire that runs inside said picafina to the proximal end ofit, then, via extension wires to the electrical pulse generator usuallyimplanted in the patient's chest. Each metallic ring is able tooriginate an electric pulse of a few volts, 90 microseconds pulsewidth,180 Hz frequency (that is, 5.55 milliseconds between pulses), alltypical values, varying from patient to patient, also varying with timeon the same patient. The pulsewidth and frequency are usually the samefor all patients, while the voltage depends on the patient, as well aswhich rings are connected. It is conjectured that the requiredvariations in the applied electric potential (voltage) are consequenceof changes in impedance perhaps caused by deposits on the ring-shapedelectrodes, but the reasons for this do not impact our invention.Examples of current art picafinas can be seen at the web referenceMedtronic (2009).

Dennis D. Elsberry, Mark Rise and Gary King (Elsberry (2000)) disclosedin 2000 a device that relies on both drug and electrical currentdelivery to affected areas of the brain, as a control to motiondisorders, as our invention does. Their device lacks the flexibility ofchoice of electrical initiation point that our device has. Our device isonly electrical, not chemical though, as are the majority of current DBS(Deep Brain Stimulation).

The multiplicity of contacts also serve to adjust the exact point atwhich the electrical current is injected into the brain, because it isknown to be difficult for the neurosurgeon to position said picafina ona target area that the neurosurgeon cannot see inside the brain, withprecision better than a few millimeters away from the desired location.Ultimate current injection location is adjusted by selecting one orother (or several) of said contacts. Ring selection, and voltageselection as well, are made after surgery, in what is known asprogramming sessions, during which information is send by telemetry(radio waves, magnetic links, or their equivalents), during which thedevice is adjusted for the particular needs of the patient.

Current art suffers from many problems, some of which are as follows. Ifthe electrical contacts are circular rings, the current is injected 360°around the picafina, approximately the same amount in all directions,and reaching the same distance from the picafina on all directions.Therefore current art does not solve the problem of directionality,apparently because nobody has been able to have a large number ofpoint-like smaller electrical contacts all over the picafina, andcapable of being independently turned on or off as needed. This lack ofdirectionality is not good because the picafina is seldom positioned atthe dead center of the target location—the surgeon cannot see inside thebrain as he/she inserts the picafina, and the regions look the sameanyway, so even if the surgeon were able to see the region near thepicafina when it is inserted, it would make little difference for itspositioning. The surgeon can, and indeed does, apply current as he/sheinserts the device, then ask the patient, who is awake during surgery,what he/she feels or thinks, which feelings and thoughts are influencedby the electrical input, from which the surgeon can determine where thepicafina is at that moment. Successive observations, during surgery, ofthe effects of electric stimulation as the neurosurgeon inserts deeperthe device allows him/her to eventually find the target location—buthardly the dead center of the target location. Indeed, though therelative position of all brain structures is substantially the same onall patients, their physical sizes, and therefore their absoluteposition with respect to any fiducial mark, say, the picafina's entrancehole on the skull, is not the same. This is true for internal as well asexternal features: all humans have their noses above their mouths buttheir absolute distances measured from, say, the forehead, vary fromindividual to individual. It follows that the electrode positioning isless accurate than desirable. Exact position of the picafina is alsodifficult because of the target regions are usually small, of the orderof a few mm only. This imprecision in positioning causes then thateither the current will not spread through the whole volume of interest,or else will spread outside it (see FIGS. 10 a and 10 b). Neither issatisfactory, because when the electrical current does not perfuse thetarget area there is under-treatment, while when the current invadesnearby areas there may occur side effects due to stimulations of areasthat are not intended to be stimulated. Neither is good for the patient.Both cases are known to exist, and because no solution has been found tocontrol the injected electric current to different distances towarddifferent directions, neurologists just accept them as fact-of-life. Ifthe picafina is of a newer type, already in the market, with square orcircular pads, the current can be injected in one or more directions, asneeded, but with insufficient positional control, also not ideal for thepatient. The inventors know of a Medtronic Inc. (710 MedtronicParkway/Minneapolis, Minn. 55432-5604) picafina with 12 small pads ofapproximately 1 mm diameter, which is insufficient in number toprecisely direct the injected current towards a preferred direction. Itappears that Medtronic is trying to solve the directional problem buthave been unable to add more pads, most likely due to lack of space forindividual wires inside the picafina. Indeed, the very introduction ofthe few individual electrical contacts indicate that the need for manycontrollable points is known, though the solution has been eluding thepractitioners of the art. Our invention solves this problem ofcontrolling a large number of electrical pads, a known problem whichsolution have been eluding the practitioners of the art.

It stands to reason that in all cases when the inserting rod is close tothe edge of the target region, shooting the current in all directions isnot desirable, as the current will enter in areas that would be betterleft alone, as they are functioning normally. Indeed, DBS side effectsare known to occur, which can be of a motor nature, as facial pulling,etc. but also of a mood or personality nature, includingincreased/decreased aggressiveness, depression/elation, etc. It istherefore desirable to have a means and a method to direct theelectrical current into some specific direction only, starting from theimperfect positioning of the picafina, a problem that is not addressedby exiting DBS devices.

Analyzing the disclosed inventions and products in the market, it seemsthat the practitioners of the art are all aware of the desirability ofhaving available the possibility of precisely controlling the point ofinsertion of the stimulating current in the brain (or heart, or spinalcolumn, or etc.), for which only the obvious solution has been tried,which is to precisely position the stimulating electrode in the targetregion. Another possibility was never investigated, which is to implanta large number of small electrodes in the general vicinity of the targetarea, followed by the selection of the correct initiation point out ofthe large number of them. It seems that the last possible solution havenot been tried because of the large number of wires necessary to connecteach pad or contact to the electric power and electronics circuitryoutside of the inserted electrode.

Other details on the current art picafina are known to the ones skilledin the art, while still others are unknown manufacturers' trade secret.

Objects and Advantages

Accordingly, several objects and advantages of my invention are

1. The possibility of controlling a large number of electrical pads forelectrical current injection or measurements from a multiplicity ofpoints,

2. The possibility of controlling which said pads are connected or not,at any given time, with capabilities of making such selection after thedevice is implanted in the patient, therefore selecting the measurementlocation with accuracy of the order of the separation between the pads,

3. The possibility of having many pads sharing the power wires andground,

4. The possibility of having a small number of wires and a much largernumber of electrical pads capable of initiating electrical stimulation,

5. The possibility of effectively using the small space available forconnecting wires in the long and narrow picafina body, so as to have amuch larger number of electrical initiating pads than wires runninginside said picafina,

6. Releasing the picafina from having a dedicated wire running throughthe length of the picafina to each said pads, because there is notenough room in the body of the picafina for many wires,

7. The possibility of housing and running through the picafina's limitedspace a smaller number of controlling wires from O&A (Objects andAdvantages) #1, when a larger number of wires would be impossible tofit.

8. The possibility of having some control on the direction and radialdistance of the injected current in DBS with the adjustment of the sizeand shape of the compound electrical pad (the aggregate of many smallpads), which occurs due to the effect known as “field shaping”,

9. The decrease or elimination of electrical currents in adjacent partsto the target volume that are not intended to be electricallystimulated, therefore reducing known and/or unwanted side effects.

10. To conscribe the current injected in the brain by said picafinawithin a better defined angular distribution when compared with priorart, keeping it conscribed to the desirable area.

11. To conscribe the current injected in the brain by said picafinawithin a better defined radial distance from said picafina, whencompared with prior art, keeping said current conscribed to thedesirable area,

12. Approximately shaping the form of the volume around said picafina onwhich electric current is injected, to better conform to the targetregion

13. To further conscribe the injected current to a more preciselydefined target volume in the vicinity of said picafina and conformingmore with the target volume than prior art picafinas.

14. To offer a means and a method to direct the electrical current intosome specific direction only, starting from the imperfect positioning ofthe picafina.

Other objects and advantages include increasing battery life as aconsequence of the elimination of current flow in unwanted brain areas,which is a valuable improvement on a battery operated device whichrequires invasive surgery for battery replacement when said battery usesup all the stored energy.

Thus one of the problems that this invention solves is how to make avery large number of electrical pads on the surface of said picafina, insuch a way that each of said pads can be individually connected to anelectrical energy source. Further, besides making asymmetric electricfields and currents around the supporting picafina, preferentiallydirected toward one particular direction, this invention permits someshaping of the electric field in the vicinity of said picafina, which inturn keep the injected current in some desired brain locations, orparticular shapes, around the picafina, further confining the current tothe most desirable brain location. Such shaping of the electric field isknown in physics and mathematics as field shaping, and is widely used,including in medicine. Nedzi (1993) describes one such use, in this casefor radiation therapy. More details about field shaping can be found inReitz (1980) and Jackson (1975). Summing up, one of the objectives ofthis invention is to provide a physical means and a method to confinethe electric current injected in the brain to an arbitrarily shapedvolume that can occupy a part only of the surrounding space around thepenetrating rod that supports the electrode.

Indeed, on a picafina with hundreds or thousands of pads for electricalstimulation, it would be from difficult to impossible to dedicate apower wire to each point-like electrode on said picafina, the difficultyincreasing with larger number of electrodes. The electrodes in thestimulator of our invention are instead all connected to the same powercarrying wire, or to a few of them, through a dedicated digital switchthat can be turned on and off with a digital addressing system.Moreover, since the objective is to keep a plurality of point-likeelectrodes active at the same time, instead of being active only whileaddressed, the address switch also contains a delay line which keeps thepower switch closed (on) for some time after having been addressed.Given the stimulation pulse length, which is of the order of 100 μs, andthe time needed to assert each address line, which is of the order of afew ns, or 10,000 times shorter, the total time elapsed from addressinga first point-like electrode to a total of a few hundreds electrodes (ata few ns each) is still less than 1 μs. Thus, the delay between theindividual point-like electrodes is negligible with respect to the totalpulse width, which in turn means that the biological effect occurs as ifthe electrodes were simultaneously turned on/off. Note also that allelectrical neuron signals occur over times of ms, which is one milliontimes longer than the delay in assertion between one electrode and thenext.

Alternatively, there is a possible latch to keep the electrode tipindefinitely connected to the power source, in which case the pulseshape is created by the electronics that controls the battery output, asin current devices.

Further objects and advantages of my invention will become apparent froma consideration of the drawings and ensuing description.

SUMMARY

The invention is a method and a means to provide a large number ofelectrical pads from which electrical current can be injected in liveanimal tissues, as in artificial muscles, heart pacemakers anddefibrillators, and specially in neural tissues in general, as spine andbrain, as well as other similar applications. The invention can also beused on the other direction, to make electrical measurements of theelectrical activity of animal cells, measurements that can add in thedetermination of the placement and level of electrical stimulation. Theneed for a large number of pads, or points from where to inject theelectrical current, exists because it is impossible to position thedevice with any accuracy, so that final place adjustment is made bytrial and error trying one (or a group) of pads until the best one(s) is(are) discovered.

The need for such a large number of pads has been recognized for a longtime, but never a solution was found on how to accommodate the largenumber of wires in the small space available, one wire for each pad,even if a common ground is used. Our invention solves this problem usinga single power wire common to all pads, that is in turn connected to asmany pads as necessary with a digital addressing system that turns on orselect any desired pad with a smaller number of address lines (wires).

This second problem is solved by our invention with a delay line, whichcauses that any pad that is turned on stays on for a selected time afterthe address line is changed to select another pad. The pulsewidth (timeon) is necessarily on the order of milliseconds (typically 0.1 to fewms), compatible with biological times, while the address assertion (timeto assert a new address on the bus) is of the order of few nanoseconds(frequency of order 100s MHz), typical of modern electronics. It followsthat the address change is so fast when compared with the other timesinvolved as to be instantaneous from the point of view of the biologicalevents and pulsewidth. This combination of virtually instantaneousaddress line selection of pads with a much longer (known as “infinite”in science and engineering) power on time, creates the desired result ofa multiplicity of pads (virtually) on at the same time for the desiredduration.

DRAWINGS

FIG. 1 shows the picafina of our invention with a possible configurationof circular shaped electrodes.

FIG. 2 shows the picafina of our invention also with electrodes equallyspace as in FIG. 1 but with electrodes of a square shape.

FIG. 3 shows the picafina of our invention also with electrodes equallyspaced as in FIG. 1 but with elongated electrodes along thecircumference direction.

FIGS. 4 a, 4 b, show another version of the picafina of our inventionwith a larger number of smaller electrodes for a larger electrodedensity as compared with FIGS. 1 through 3. FIGS. 4 a and 4 b, depict aside view and proximal end of this version.

FIGS. 5 a and 5 b show variations on current art of picafina that can beimplemented with existing technologies that allow a small number ofelectrical contacts.

FIGS. 6 a and 6 b show two alternate profiles for the picafina.

FIGS. 7 a and 7 b show the location of the address decoders and electricswitches associated with each electrode pad and one of them with themost important (not all) connections indicated. Note that FIG. 7 a is anexample of each one of the multiple address decoders and switches, oneat each z-value, that is one at each cross section at a fixed distancefrom one of the two extremities of the picafina of our invention.

FIGS. 8 a and 8 b show one of the possible implementations of theelectronics used for the alternative embodiment of our invention usingseveral measuring pads and several signal carrying wires, including theswitches to select the pads and the demultiplexers to select the signalcarrying wires. These two figures are an extension of FIGS. 7 a and 7 b,with the added possibility of multiple current carrying wires to set theelectrode pads at different voltage levels and/of at different timepatterns. FIG. 8 b shows a detailed block diagram of a possibleelectrical connection of one electrical pad of the picafina of ourinvention. This is a exemplary system, others being possible.

FIGS. 9 a and 9 b are possible implementations of an address decoders.Our invention is not limited to this particular form of address decoder,which is here shown only as an example. Indeed, our invention does notimprove on the art of address decoding, which is a mature art inelectronics and is just used here.

FIG. 10 shows a main embodiment of my invention with 12 electric padsaround the circumference of the picafina, 16 ring of pads along thez-dimension, and no electric pad on the tip of the picafina.

FIG. 11 shows a window environment with the drop-down menus forprogramming the Doctor's Programming Unit (DPU)

FIG. 12 shows a redundant wiring at the proximal end of the picafina ofmy invention. Each wire is repeated for redundancy, to be used in caseof wire breaking, which is common given the small size of the wire.

FIGS. 13 a and 13 b show two possibilities of electrical currentreaching less (a) and more (b) then the target volume using current arttechnology, while FIG. 13 c show the result on the current reach ofdifferent voltage levels on the pads. This simple description is wellknown in physics and electronics by the name of field-shaping, which ismore complex than this representation here, and is a well-known effectwhich can be used to achieve better results only with the larger andindividually controlled pads of our invention.

j. DRAWINGS List of Reference Numerals

-   h_1=length of the distal part of the picafina, which is devoid of    electrical pads.-   h_2=length of the middle part of the picafina, which is populated    with electrical pads.-   h_3=length of the proximal part of the picafina, which is devoid of    electrical pads.-   13_1=Cross section of the picafina, perpendicular to its major axis    (z-axis).-   13_2=Area that receives the electrical stimulation.-   13_3=Target region, area that needs to receive stimulation.-   100=body of picafina of my invention.-   110_xx_yy=pads/electrical contacts on the surface of body 100.-   810_xx_yy=on/off transistor that connect each electrical pad to the    electrical power source, also indicated as 810 _(x), when referring    to any of the possible transistors, also indicated as SW or SW_(x)    when referring to the transistors as their function of switches.-   811_xx_yy=on/off switches for power wires (either fixed voltage or    fixed current) that brings power to the stimulating pads 110 on the    picafina's surface.-   820_xx_yy=timer or pulse stretcher, where xx indicates which “ring”    or z-distance, while yy indicates which of the 12 pads in each    “ring”. In the main embodiment xx takes any value from 01 to 16,    while yy takes any value from 01 to 12.-   830_xx_yy=address decoders.-   840_xx_yy=address decoders for different voltage options.-   200=address lines or address bus for stimulating pads.-   201=address lines or address bus for power carrying wires for the    stimulating pads.-   200prox=proximal side of digital address lines for selection of    stimulating pads 110.-   201prox=proximal side of digital address line for power carrying    wires.-   210prox=proximal side of electrical power to power the picafina    electronics.-   211prox=proximal side of stimulation power carrying wire (one 211 in    main embodiment, few 211 in claimed secondary embodiment.-   212=ground wire.-   latch=latching signal wire.-   1200=microcontroller.-   1230=current controller.

DETAILED DESCRIPTION Main Embodiment

For the disclosure of my invention I will use the example of deep brainstimulation (DBS), it being understood that the same method applies toother stimulators, with the modifications that are obvious to onesfamiliar with the art. A similar method also applies to measuringelectrodes, that is, devices to measure the electrical signals in livingorganisms. A similar method also applies to bi-directional devices,which are capable of both reading electrical activity in the neurons andalso capable of stimulating other neurons, or the same neurons after themeasurements were made, which are very useful for electrical stimulationbecause the current state of the neurons can give indications of thelocation, type and level of electrical pulses to be applied.

I start with a succinct description suitable for electrical engineers,then follow with a detailed description for readers with non-electronicbackgrounds. The problem is to deliver electric current to internal bodyparts, as brain, spinal cord, heart or muscles, which may even be notvisually accessible, or that for some any other reason cannot beprecisely located. A source, here called picafina, larger than the pointof delivery of current, is then approximately placed in the targetlocation, such source covered with a multitude of surface electrodes,here called electrode tips, or just tips, or pads, which are of such asize and placement as to cover all the desired target areas and more.After a surgeon implants such source in the general vicinity of thetarget area, a medically trained person can select which pads to use,typically by observing the desired effect from turning on one pad at atime, or a combination of pads at a time. It is relatively easy to makea very large number of small pads to precisely control the place fromwhich to inject current, but it turns out that there is a stringentlimit on the number of wires which are needed to connect these pads tothe battery and controlling electronic circuit, because these wires haveto go through the limited space available in the body into which thepicafina must be inserted. So current technology stimulators, inanimals, including human beings, the limited space available limits thenumber of pads to the number of wires possible to use—each pad needs awire connecting it to the power source. Current technology can put a fewdozen wires at maximum in the limited available space, therefore a fewdozen pads only can be used (Gregoire Courtine, private communication).To make use of more pads than wires, this invention discloses the use ofa digital addressing system coupled with a timed delay system, and alatch, which, under the control of a microcontroller or equivalentdevice, turns on a subset of a large number of pads capable ofdelivering electric current to the body. The subset is chosen with theobjective of delivering the current to selected parts of the body, theparts that are in the neighborhood of the selected pads. The timed delaykeeps the current on for a pre-determined time after selection of eachpad, because typically it is desired to have many pads on at the sametime, so any selected pad have to stay on after another pad, or manypads, is (are) being selected. The timed delay is much longer than thetime taken to select each pad (time for new selection<<time pad on),such that out of a negligible small initial time delay (order ofnanoseconds) all pads are on together (order of 100 microseconds).Alternatively, once a pad(s) is (are) selected, they stay onindefinitely, in which case the electronic controlling associated withthe battery turns the current on and off according to the desiredpattern, in which case all the pads are on together and off together.This latter possibility is more similar to current art. It lacks theprovision to add a delay between the pads, which is offered by the timedelay, which offers more options for treatment.

The invention can also be used on the other direction, selecting one outof a plurality of pads from which to read electric potentials, in thiscase to obtain information about the body, instead of to act on it. Itwill be apparent to the ones skilled in the art that readings the actualneuronal firing can give information to the type of stimulation requiredto achieve the objective, which in this main embodiment of DBS is tostop Parkinson disease tremor.

Detailed Description

FIG. 10 shows a perspective view of a basic version of our invention fora particular main embodiment used for deep brain stimulation. For brainstimulation, the objective is to inject electrical currents in selectedareas of the brain, the objective being to modify some brain activity,often motor in nature, as in Parkinson disease, or epilepsy, but othercharacteristics are also modifiable, including mood and personality. Itdisplays a possible main embodiment of my invention omitting the innerelectrical connections and structures, which are described immediatelyafter. The picafina's outer surface is made of some material compatiblewith human tissues, e.g., polyurethane (for the bulk) and gold ortitanium (for the metallic pads), these being only examples used incurrent art picafinas, many other materials being possible, and theparticular material being irrelevant for our invention. The body has tobe of a material that does not conduct electricity, while the pads aremade of a material that is a good electrical conductor, as a metal. Thepads are to serve as starting points of electrical currents somewhere inthe body, which, for the main embodiment, is deep inside the brain. Thesame principle works in reverse, to read one out of a plurality ofelectrodes to obtain information, but the reading device is different insome characteristics.

Starting from the distal tip of the device, FIG. 10, near the concaveend of the picafina of our invention, and following only the externalfeatures of it, there is a solid, smooth part of length h_1=2.5 mm(typical value), after which the electrical pads start, on a lengthh_2=20 mm, followed by another smooth part on a length h_3=47.5 mm, fora total length h_total=70 mm (typical values, see FIG. 10). The distalend is shaped as indicated in FIG. 10 to facilitate the insertion of thepicafina into the mushy brain tissue, while the proximal end (near theskull) is flat, to facilitate the electrical connections and mechanicalsealing. The proximal extremity is usually flush with the skull, towhich it is affixed with screws or their equivalents (not shown). At thepicafina's proximal end there are a number of wire endings with thenecessary means for connection to extension wires that make connectionsto the outside of the skull. In this main embodiment there is only onepower wire (voltage), one ground wire, and a plurality of address wires(8 in this main embodiment). It is also possible to have a deselectline, or wire, the function of which is to disconnect all switches andgates, or turn them all off.

The dimensions indicated in FIG. 10 are typical, for concreteness of thedescription herein, different values to adapt to different situationsbeing possible, as known by the practitioners of the art, and thesedimensions should not be therefore considered restrictive to theinvention, but only typical and compatible with the particularapplication detailed here: Deep Brain Stimulation (DBS). Moreover, thenumber of pads is here artificially set to a low value to make thedrawings and the description easier to follow, a real case picafinahaving many times more electrical pads than the illustrative exampleused here. In this main embodiment described here there are only 192pads, numbered not sequentially but accordingly to the rings they belongas 110_01_01, 110_01_02, 110_01_03 etc, until 110_01_12, for the 12 mostdistal pads (i.e., on the most distal ring of pads), then 110_02_01,etc. for the next ring, etc. until the most proximal ring of pads, whichis numbered 110_16_01, etc., in FIG. 10. These pads are made of metal,titanium in the maim embodiment, but any other material that iscompatible with human tissue and also relatively good conductors ofelectricity is suitable. These pads are to be the initiation points toelectrical currents to be injected inside a patient's brain. With theindicated dimensions, typical pad diameter is 0.666 millimeters andedge-to-edge separation is also 0.667 millimeters along thecircumference, so center-to-center separation between the pads is 1.333millimeters along any circumference at a fixed distance from any of theends (fixed z dimension). On a 5 mm. diameter picafina, there are 12such pads on a circle, at any particular distance from any of the ends.Along the z coordinate the separation between pads is also 1.333 mm(typical dimension), making 16 such circles populated with 12 pads each,making a total of 192 pads on a z dimension length equal to 20 mm (h_2).These are possible dimensions, in no way to be taken as restricting myinvention, as many other values being compatible with my invention, asknown to the ones skilled in the art. The length h_total must be such asto reach the particular target area, and the diameter must be compatiblewith the size of the animal in which it is used.

Continuing towards the proximal end of the picafina of my invention,beyond the region marked h_2 populated with electrical pads, the body100 is bare, no pads, corresponding to areas on which electricalstimulation is not expected or needed. Typical dimension is h_3=47.5 mm,for a total length h_total=70 mm=7 cm, which is a typical value for DBS.

At the proximal end of the picafina there is a plurality of wires whichmay have special connectors to make the electrical connection toextension wires to the electronic circuits and battery or any otherpower source, which are described further down in this section. Saidconnectors could be separated as one harness with 8 contacts for theaddress lines 200 and a separate harness for the power wires 210, 211,ground wire, and other wires as necessary, as shown in perspective atFIG. 10, or all the wires could end on a single harness, or each wirecould have its own dedicated connector, or any combination of these,because the particular form of connecting the wires is not part of thisinvention. The technology for the connectors is an established art, myinvention making no improvement on this aspect of the picafina.Moreover, the technology used for the wire connections used in currentart deep brain stimulators is suitable for my invention. For purposes ofdescription we are here dividing these wires in address lines and powerlines, concepts that are explained below but are standard concepts inelectrical engineering.

FIG. 4 b depicts a flat view of a possible proximal end of the picafina100 of our invention. The positioning of the wires is not part of ourinvention, the particular location displayed at FIGS. 10 and 4 b beingexemplary only.

Describing now the inner structure of the picafina 100, also startingfrom the distal end of it, or lower part of FIG. 10, the first 2.5 mm ofit (h_1, typical dimensions) have no features inside. In the particularpreferred embodiment, said distal end is solid and made of the samecompatible material as the external surface of the picafina, but this isnot necessary, it being possible to have a hollow interior, or aninterior made of a different material then the exterior surface, thisdetail not being part of the invention herein disclosed. It is onlynecessary that picafina 100 has sufficient stiffness and durability.Moving towards the proximal end of the picafina, on its outer surface,at the distance h_1 from said distal end (see FIG. 10), there is a firstset of electrical contacts or pads, 110_01_xx (xx running from 01 to12), along an imaginary ring on its outer surface, at a fixedz-coordinate. With the typical, exemplifying dimensions given above,1.33 millimeters center-to-center distance between electrical pads,picafina radius R=2.5 mm, there are 12 such pads around the picafina'souter surface making the first ring of pads. These electrical pads areconnected to electrical circuits inside de picafina, as we proceed todescribe.

FIG. 7 a is a conceptual drawings of a cross section of the picafina ofour invention, made perpendicular to the long, or vertical, or zdimension shown in FIG. 10, made at a distance approximately 2.5millimeters from the distal end, that is, at the plane of the lowest(closest to the distal end) ring of electrical pads. What is shown inFIG. 7 a is not a drawing of what would be seen in reality, with amicroscope, but a representation of the electronics at that position,the actual transistor construction being out of the scope of theinvention, not included in the invention, and part of the old art ofsemiconductor and printed circuit board manufacture. While FIG. 7 adepicts a schematic (simplified) view of the electronics circuits thatdetermine our invention, FIG. 7 b shows in more detail the electronicsfor one single electrical pad, one of the 12 repeated circuits aroundthe circle at FIG. 7 a. The reader is requested to pay particularattention to these figures that detail the electronics of the picafinaof my invention. Referring to FIG. 7 b, when address for pad 110_01_01is asserted on the address bus 200, that is, when 200 has value (00000001) the address decoder 830_01_01 recognizes the address and makes itsoutput to go high, while none of the other address decoders recognizesthe address as theirs, so all other address decoders keep their outputslow. This in turn causes the output of timer or pulse stretcher820_01_01 to go high (but none of the other timers) and to stay in thathigh state for a predetermined length of time, which for the mainembodiment is 90 microseconds. As long as the output of the timer/delay820_01_01 is in the high state, which turns switch 810_01_01 to theconducting state thereby connecting the measuring pad 110_01_01 to thepower wire that runs along the length of the picafina, all the way toits proximal extremity, where the necessary connections are made, inthis case, the connection of the power wire to an appropriate source ofelectrical power, at some pre-assigned voltage, for example. Switch810_01_01 could be, for example, an NPN transistor (not shown) with thenecessary biasing, so whenever there is current at the base oftransistor 810_01_01, which is controlled by resistor 805_01_01 (notshown), said transistor is on the low impedance state (conductingstate), whereby pad 110_01_01 is connected to the power wire. Whiletransistor 810_01_01 is on, the electrical pad 110_01_01 sees a lowimpedance connection to V_cc, or, in other words, it is connected to thepower supply at V_cc minus the (small) voltage drop at transistor810_01_01. It follows that, as a consequence of this sequence of events,current flows out of electrical pad 110_01_01 into the patient's brain,causing the desired effect on its function for the duration of the pulsefrom timer/delay 820_01_01, which is 90 microseconds for this mainembodiment, or the standard time currently adopted for the pulses out ofthe rings in current art picafinas. None of the other pads is turned onat this stage.

FIG. 7 b shows the electrical connections between the main conceptualblocks of my invention: the address decoder, the timer/delay and theelectronic switch, and the wiring for them, the address bus and thepower wire.

A few nanoseconds after the above event is completed, and as fast asmicrocontroller 1200 (not shown) can implement new events, it asserts anew address on address bus 200, say 0000-0010_B=02_D=02_H (binary,decimal and hex representation), which is the next address, recognizedby address decoder 830_01_02 as its own, and then, mutatis mutandis, thesame process described in the above paragraph repeats for pad 110_01_02,which will then stay on concomitantly with pad 120_01_01 next to it,because previously selected pads continue on for 90 microseconds, a verylong time for electronic events.

As microcontroller asserts all addresses residing in its memory, whichcorresponds to the pads programmed to inject current in the patient'sbrain, all pre-programmed pads are turned on, this occurring with a timedelay between each selection much smaller than the 90 microseconds thatthe pulse lasts for this particular embodiment, resulting in that forall practical purposes the pads are on together. After 90 microsecondsthe timer/delay reach the end and begin turning each pad off in quicksuccession, which ends one cycle. Another cycle repeating all thesesteps is started after a time equal to 5.55 milliseconds for this mainembodiment, or at a frequency f=180 Hz, the full sequence repeatingindefinitely for this main embodiment, though it is conceivable that insome circumstances the sequence could be interrupted during sleeping orother times of the day.

FIGS. 9 a and 9 b show two possible implementations of address decoder830. The inputs to each AND gate are preceded or not by inverters, asneeded to make the address for a particular electric pad. FIG. 9 adecodes for address 01_D=0001_B=01_H, or the first pad on the first, ormost distal “ring” of pads, while FIG. 9 b decodes for address12_D=1100_B=OC__H (8+4), which is the last pad on the same most distal“ring” of pads. As seen, with an appropriate combination of invertersany desirable address can be selected by address decoder 830. This isonly an exemplary version, many other possibilities existing for addressdecoders, which is a mature field in digital electronics, not part of myinvention and any of the variants being possible for my invention. Inthe preferred embodiment of my invention said address decoder is alsogrown on the substrate of each layer that serves a particular set ofpads 110 at a fixed distance from the ends of the picafina, for example,the 12 pads described above, part of the most distal “ring” of pads. Asis the case for the switch and pulse stretcher, the address decodershould be build in such a way as to minimize power consumption.

Returning to FIG. 7 a it shows the electronic circuits existing at thatcross section, not necessarily at their exact position, as thepositioning of the electronic parts is not part of my invention, butonly their function and logical connection. The detailed implementationof the electrical connections are known in the art of electronics. Inparticular the actual transistors and electrical connecting wires mostlikely will in practice be not on a single plane but on differentlayers, according to the established art of transistor and printedcircuit board manufacture. Both transistor and printed circuit boardsare mature fields on which my invention makes no improvements. Ourinvention works with this electronics that are described in this layeror some of its electronics equivalents.

For the main embodiment described, which has 16 “rings” of pads, each ata different z-coordinate, there are 16 circuits similar to the circuitdescribed above, except for the addresses, which is unique for each pad.

Between each plane of electronics that feed power to each of the 16“rings” of pads, there are vertical “wires”, which are in this case aremade using the established techniques of semiconductor manufacture or ofprinted board manufacture, or a combination of these, such “wires”connecting all the 8 address lines 200, the single “wire” 211 thatcarries the electrical power to the pads, the wire 210 that carries thepower to the picafina electronics, the ground wire, and other wires thatmay be needed. Such vertical wires connecting in parallel all 16 planarcircuits described above continue to the proximal end of the picafina,where they end at the connectors 200, 210 and 211 shown at FIGS. 10 and4 b.

Said wires running inside the picafina of my invention are, in thepreferred embodiment here described, constructed with some combinationof semiconductor manufacture, printed circuit technology and manualsoldering. For example, all the address decoderes 830 and the switches810 that serve a particular set of pads at a fixed axial distance fromthe ends of the picafina (say pads 120_01_01 through 120_01_12) could bemade of current technology of semiconductor manufacture, and theirconnection to each of the pads could be individually made by atechnician at fabrication, while the vertical connections from layer tolayer could be made with the existing technology of vias, a known methodin printed circuit technology. But printed circuit technology, orsemiconductor manufacture, or manual soldering are not intended to berestrictive for my invention, any other equivalent technology or anycombination of them being acceptable.

The switch 810 can be as simple as an npn transistor, as indicated inthe schematic diagrams of the figures disclosing the main embodiment, orit can be a more sophisticated circuit, as known to the practitioners ofthe art of electronics, and the time delay/pulse stretcher can be any ofthe available circuits used by electronics engineers or it can be a new,especially designed circuit, the particular design of the pulsestretcher not changing the invention but just that such a circuit existstogether with the on/off switch. One example of a pulse stretcher can bethe very much used 555, manufactured by many chip manufacturers, set fora one-shot mode and with the appropriate pulse width set by resistorsand capacitors as per manufacturer instructions. In the preferredembodiment of my invention the address decoder, the pulse stretcher andthe switch 810 are grown on the substrate of each layer that serves aparticular set of electrode pads 110 at a fixed distance from the endsof said picafina, for example, the 12 contact pads described above. Forthe switch, the pulse stretcher and all other electronics described inmy invention, it is preferable that they use as few components aspossible to conserve energy supplied by a battery.

From the connectors shown at the proximal end of the picafina at FIGS.10 and 4 b, wires of the necessary length (not shown) connect theproximal end of the picafina to the electrical battery and electronicscircuit, including microcontroller 1200 (see FIG. 12 for a redundantversion of the wire harness). Said battery and electronics are usuallyinside a sealed box (not shown) implanted in the torso of the patient,with the wires generally running under the scalpel, behind the ear, downthe neck to the torso, but the particular places for the wires are notpart of this invention. The position of the battery and electronics arenot part of this invention; most current art battery and electronics areimplanted in the patient's torso but some are also implanted in a cavitydrilled on the skull, near the picafina.

A sealed box containing the battery and the electronics is connected tothe address bus 200, power wires 210 and 211, ground wire and any otherwire, as needed. Said power wire 211 is connected to a programmabledevice, controlled by microcontroller 1200 or microprocessor, ormicrocontroller, or DSP, either commercially available or especiallydesigned, or any of its equivalents, which sets the output voltage toany of the possible values compatible with the battery and theelectronics. Said programmable device, under control of the instructionssent to the microcontroller 1200 by the telecommunication link(described in the sequel), adjusts the voltage to some desirable value,determined by trial and error by the medical practitioner as he/sheobserves the effect on the patient that occur as he/she adjusts thevoltage to several values, preferably following either his/herexperience, or following some method indicated by the equipmentmanufacturer, as described in the sequel.

During normal operation, that is, after the adjusting phase described inthe sequel, microcontroller 1200 has stored in memory, as downloaded bya telecommunication link described elsewhere, a list of numbers whichare the addresses of the pads to turn on, which, under the control of apre-stored program, is put on the address bus 200 one at a time, inquick succession, to turn on the pads as required. Said list of addresscan be as few as one single address of a single pad, or a large numberof addresses.

The electronic circuit that controls the stimulator is comprised of ananalog part and a digital part. The analog part of the electroniccircuit adjusts the electrical energy source's output (e.g., a battery,a capacitor, or the like) for either a constant electric potential (thatis, a constant voltage) or a constant current to be delivered to thepads at the picafina. The electric energy source output is connected tothe power wires 210 and 211 that goes to said picafina, and to theground wire as well, connecting to the power wires at said picafina'sproximal end, which is generally at the burr hole aperture on thepatient's skull. The electronics adjusts the electric energy deliveredto the picafina for a constant voltage, typical values are 3 to 5 V, orit adjusts the electric current, typical values are 3 to 5 mAinstantaneous current, but these are just exemplary values most commonlyused in current art but that may deviate as the particular needs of eachpatient dictates, and the device should be designed to work on a rangeseveral times the typical value. There ought to have some system toadjust the voltage/current output for a particular value, which dependson the particular patient and may need to be changed as time goes on forthe same patient, and one exemplary such system is described below. Suchelectric potential (voltage) or current changes are generallyimplemented without direct contact, e.g., via radio pulses, magneticinduction or some other convenient method, which is not part of thisinvention, as it is part of the current art. This part is not describedin this invention because it is the current art of electric stimulators,brain stimulators, nerve stimulators, etc., so it is not part of myinvention, and they can be any of the existing circuits known to thepractitioners of the art.

The digital part of the electronics is a device based on what isgenerally known as Digital Programmable Device (DPD), as amicroprocessor, a microcontroller, a Digital Signal Processor (DSP), orthe like, including a memory part and ADC (Analog-to-Digital Converter)and/or DAC (Digital-to-Analog Converter). A microcontroller betterdescribes the DPD, but it can also be divided in a combination of amicroprocessor and a memory part and an ADC/DAC. It contains a digitalmemory part in which a program can be stored, as well as numericalparameters and even results from readings of the patient's condition atpre-assigned times or when a pre-assigned condition occurs. The storedprogram contains, among other things, the instructions to periodicallyturn on and off each of the electric contacts 110 described above. As iswell known in the art, all DPD work with an oscillator, known as a clockor system clock, as shown by the standard PC, that powers up with thecorrect current date/time-of-the-day, usually on the screen's lowerright hand side. The system clock is able to keep track of real time.

Said DPD is capable of creating the addresses of each of the padsselected by the medical practitioner, one at a time, in rapidsuccession, until all desired pads have been selected—usually not all ofthem. The pads are selected according to the programmed sequencedetermined by the medical practitioner. Said selection is made eitherusing neurological knowledge, or prior experience, or just trial anderror, or any combination of these methods. Typical times for eachaddress to be asserted on said address bus is of the order ofnanoseconds or tens of nanoseconds. The whole series of pads may beselected, one at a time, on a total time or the order of a fraction ofto a few microseconds. After the series is completed, said DPD staysquiet for a longer period, which in current art is of the order of 5milliseconds (frequency f of the order 180 Hz), after which time thewhole sequence is repeated, said DPD again asserting all the addressesin rapid succession, etc.

Said printed circuit wires are built inside said picafina, layer bylayer, horizontally, toward said electronic components and electricalcontacts on said picafina surface, all around said picafina surface, andvertically, within the height of any given contact set to the next, fromone level of contacts to the next, from the distal end of the picafinauntil all the contacts are printed on the outside surface of saidpicafina. The technology to grow (that is, to construct, or to build)the electronics inside said picafina is not part of the invention, andany of the existing art technologies can be used. For example, all theelectronics for each “ring” can be grown on a thin substrate, which islater soldered by hand by a technician, under microscope, or by anrobot-like soldering machine to said surface electrical pads and to saidvertically connecting wires. At such distance along the picafina suchthat all the surface contacts are complete, a number of standard endingpads known to people experienced in the art of printed circuits can beprinted, which can be connected to standard wires that are in turnbrought to the proximal end of said picafina, or the whole picafina canbe completely constructed by layer by layer deposition until itsproximal end.

Operation of Invention

In this section we will describe the two steps needed for the operationof the invention: the calibration and the use. Similarly as for thedescription of the invention we start with a disclosure of the operationwritten in a succinct form for electrical engineers, followed by adetailed explanation of the operation.

Operation of our Invention—Electrical Engineering Version.

Our invention discloses a system to have a very large number of padsfrom where to inject electrical current in the body, while using a muchsmaller number of wires to bring the electrical power to these pads. Theinvention operates under control of a microcontroller or similar devicethat has stored in memory a list with the digital addresses of the padsthat are to be turned on. The pads' 90 microseconds pulsewidth, as wellas the pulse repetition rate or 5.56 ms (frequency f=180 Hz) arestandard in current art and fixed in the main embodiment. These are thevalues used by existing devices, which were discovered by trial anderror, but these particular values are not intended as limitations toour invention, which operates with any pulse sequence. Themicrocontroller simply turns on in quick succession all pads that havebeen programmed to be active, then waits the necessary 5.56 ms to starta new cycle. The pads are automatically turned off after the required 90microseconds by the timer-delay associated with each, while they areturned on by the microcontroller which is usually located on thepatient's chest.

From another point of view, the operation of the invention is based oneach pad being connected to the power wire via an electronic switch 810that is turned on by a timer/delay circuit, which is turned on by aspecific address decoder associated with each pad. A microcontroller, orsimilar device, runs a program that puts on the address bus in quicksuccession all the addresses for the pads that are to be turned on. Eachpad is associated with a binary address decoder 830 that recognizes itsunique binary address. Upon recognizing its address on the address bus,the particular address decoder turns on a delay/timer, which keeps itsoutput high for the duration of the electrical pulse (that is, thepulsewidth), which, for the main embodiment is 90 microseconds, time seton the delay/timer, which in the main embodiment is fixed in hardwarebut variations of the main embodiment can have the pulsewidth set insoftware. The output of said delay/timer turns on an electronic switch,which then connects the particular pad to the voltage (or current) line211. Once turned on, the pads stay on even after its own address isdiscontinued from address bus 200 and another address is selected by themicrocontroller, staying on for the duration set on the delay/timer 820.The switching from pad to pad, that is, the execution time of theinstructions to change the addresses is much faster when compared withthe 90 microseconds the pulse lasts in the main embodiment, resultingthat all the selected pads will stay on essentially together. Moreover,there is no medical need that the pads must be synchronously active. Themicrocontroller, which is implanted in other location, usually thechest, contains the battery and all the electrical circuits necessaryfor the picafina operation. There are voltage or current regulators,which are any of the existing devices, and the same as in current art,and a microcontroller or similar device, which contains a program thatruns the innovation of my invention. The microcontroller is capable ofreceiving instructions via an electromagnetic link from an externalprogramming device here called Doctors Programming Unit (DPU). During adiscovery phase, to determine which pads to use, a medically trainedoperator, using, e.g., a windows-type environment (See FIG. 11) firstturns on individual pads or groups of them, also at different voltages(or current) levels, while observing the results, with patientcooperation. After determining the best combination of pads and voltagesthat suits the particular patient, the medical personnel downloads, fromthe DPU to the implanted microcontroller, a final program which containsthe addresses of all pads that are to be turned on, and the voltages aswell, after which a signal is sent to said microcontroller to run theprogram, which will then periodically send the necessary electricalpulses to the picafina: asserts on the address bus each of the addresseson the list, then stops until 5.56 milliseconds have elapsed (f=180 Hz),then starts the same cycle again. A lengthier explanation of theoperation of the invention follows.

Operation of My Invention—Detailed Version

After surgery and patient discharge from the hospital, the patient willschedule several visits to some medical facility (which can be the samefacility as the one that made the implant), to program the implanteddevice. This phase is similar to what is done in current art, exceptthat there are more pads to program in the device of our invention. Toprogram the implanted device the medical practitioner useselectromagnetic or magnetic communication between a unit describedfurther down, called the Doctor's Programming Unit (DPU) and theimplanted controlling unit, which is inside the patient, not physicallyaccessible after the surgery is completed and the patient sewed up.Though the implanted device is no longer physically accessible after thesurgery, its electrical properties can be adjusted and changed via radioor magnetic or other type of action-at-a-distance communication. Suchaction-at-a-distance communication is similar to the wireless controlsfor home electronics, for automobile door opening, for walkie-talkies orcell phones, for wireless network connection, etc. Accordingly, either ageneral purpose computer with the necessary communication electronics,or else a specially designed computer, are used to send to the implantedunit the necessary parameters and information. Any such device will behere referred to as the Doctor's Programming Unit (DPU), which maycontain software for several different types of implanted devices,similarly to a notebook computer containing software for many USBdevices, etc. A specially trained medical personnel, as a specializednurse, or a medical doctor, loads in this Doctor's Programming Unit thesoftware driver that is appropriate for the particular CPU implanted inthe particular patient or the appropriate program (driver in softwarelingo) is loaded automatically as when installing a USB device in anymodern computer. This process could be done under a user-friendlywindows environment similar to choosing between two word processors, asWord for Windows or WordPerfect, and it can also be that the DPUrecognizes which is the model of the patient implanted device, similarlyto a computer recognizing any particular USB device and thenautomatically loads the correct driver. It works similarly to a wirelessinternet communication with some internet provider, though thetechnology, frequencies, range, etc are not necessarily the same. Theinvention is independent of the type of communication link between theexternal Doctor's Programming Unit (DPU) and the implanted unit that isinside the patient.

There are two phases in the picafina programming: the discovery phaseand the final implementation. During the discovery phase the medicalpractitioner will, by trial and error, find which electrical pads causesthe best results for the patients, including absence of side effects,then, after or concomitantly, find also the best voltage values for thebest results. An exemplary session could be as follows. The patientarrives at his first session for the discovery phase. The medicalpractitioner loads the software that is appropriate for the particularunit that is implanted in the patient. This can be done either typingthe serial number of the device, or the name of it, or else clickingwith the mouse on an appropriate icon, as when loading a word processor,an excel spreadsheet, or other program. This program contains all thenecessary intelligence to adjust the implanted device. It contains,among other things, information on the number and position of all pads,as well as on the voltage range possible to chose. The medicalpractitioner may then start selecting the voltage to use. This could bedone, for example, from a software bottom visible on the screen, perhapsmarked “voltage level”, perhaps on the top of the screen, which, whenactivated, could offer voltage options to chose from, as when selectingthe size of letter on a word processor. Another possibility is thedisplay of a sliding scale, as used to set the volume level whenlistening to music on the computer, or when using the computer as atelephone. It is also possible to display an empty window, which allowsthe medical practitioner to type in the voltage value. Any of these andother methods are possible, and may be all offered simultaneously forthe medical practitioner to use the one with which he/she is morecomfortable. After selecting the voltage level, the medical practitionerwill need to choose the pads. When ready to choose the pads, the medicalpractitioner, still on his/her DPU, may, for example, click on asoftware bottom, perhaps next to the “voltage level” bottom, indicating“pad choice”, or any similar wordings, similar to a bottom thatindicates “font types” on a word processing, that typically exists nextto the “font size” bottom in most word processors. A drawing may bedisplayed on the screen, displaying the picafina implanted in thepatient. Using a mouse, the medical practitioner selects a pad, say, pad120_01_01, or a group of pads, say, pads 120_01_01, 120_01_02 and120_01_03. This step also uses the established conventions, e.g.,pressing the “control” key to add pads to the selected list and pressingthe “shift” key to select all the pads within a range, which arestandard choices used in many word processors, spreadsheets, etc. Uponbeing selected, the color of this (these) pad(s) on the computer screenmay change to confirm its (their) selection, or even a range of colors,each one to code for a different voltage level, or any similar method(colors not shown in figures). Alternatively the medical practitionermay type in the pad addresses he/she wants to select. It is expectedthat many options will be made available to the user.

For said selection of pads and voltage levels, the medical practitionerwill either use a system recommended by the picafina manufacturer, orwill use a system developed by him/herself to test variations of padsand voltages that are best for the patient. For example, the discoverysession may start selecting all the 12 most distal pads, that is, pads120_01_01 through 120_01_12 at a low voltage, say 0.5 V. The medicalpractitioner will then send the information from his/her DPU, via thewireless system, to the implanted unit and then press another softwarebottom that instructs the implanted unit to start sending the pulses tothe picafina. The patient will report the effect, if any. Depending onthe effect on the patient, as reported by him/her, and as observed bythe medical practitioner, this latter may increase the voltage to 1.0 Vand try again, in 0.5 V steps (or any other step) until some effect isreported by the patient or until the maximum allowed is reached, usuallynear 5 V. This series may be stopped short if undesirable side effectswere reported by the patient. At this point, if undesirable side effectswere either reported by the patient (say, depression) or observed by themedical practitioner (say, facial pulling), the medical practitioner maytry turning on a subset of the pads, say, pads 120_01_01 through120_01_06. This is the equivalent at the picafina level to selecting aparticular angular section of the ring, which physically directs thecurrent onto a particular direction only around the picafina. Themedical practitioner will try other combinations too, as indicated bygeometry and his/her experience, observing if the undesirable sideeffects appear or disappear. At this point the medical practitioner willbe investigating the current injection towards one side of the picafina,as opposed to all around it. If the undesirable side effect fails toappear when turning on a subset of the pads, then this may be anindication that this set points toward the bulk of the area-of-interest,because it is known that the picafina is often positioned at some edgeof the area-of-interest. Next the medical practitioner may use his/herDoctor's Programming Unit (DPU) to turn off all the most distal pads andturn on instead the second next ring of pads towards the proximal end ofthe picafina, pads numbered 120_02_01 through 120_02_12. He/she willagain run the series of allowed voltage levels, increasing the voltageby steps of 0.5 volts, in consultation with the patient, noting all theresults, also stopping if undesirable side effects were observed. Ifundesirable side effects were observed on the most distal set of padsbut not when a subset only of pads were turned on, the medicalpractitioner may then try the same “good” set on this second ring ofpads 120_02_xx. This may confirm the previous observation that thepicafina is located near the edge of the region-of-interest, with aparticular range of pads towards the region-of-interest.

The medical practitioner may then go to ring number 3 (120_03_xx, pads120_03_01 through 120_03_12), then ring number 4, etc, until the mostproximal ring, number 16. Upon completion of this initial series, themedical practitioner may decide to make a more detailed investigation onthe effect of some particular pads, depending on the total of reportedand observed results, and so on.

This process may come to completion in one single session or may takemore than one session, depending on the patient and on the difficulty ofthe case. When the discovery process is complete, the medicalpractitioner will make a complete selection of all the pads that causedthe best results, send the information from his/her Doctor's ProgrammingUnit (DPU) to the implanted device and, using another software bottomsend an order for the implanted device to keep that sequence runningcontinuously, or during the waking hours only, or every other hour, orsome other pattern that is needed. These choices are also available fromdrop-down menus, similar to choosing line spacing, indentation, etc. ona word processor. FIG. 11 displays a possible window environment for useon this DPU.

Inside the patient the system works as follows. Microcontroller 1200,following the program downloaded by the Doctor's Programming Unit, andafter receiving a “go” instruction from said DPU, and as long as it doesnot receive a countering “stop” instruction from said DPU, asserts onthe address bus 200 the address of the first pad on the list created bythe DPU, say pad 120_01_01. This being the first pad on the picafina,the address may be, for example, 00000001B=01H=01D (in binary, hex anddecimal notation, respectively). At the picafina the address decodercorresponding to the selected pad recognizes the address and set highits output, which in turn starts the timer that keeps its associatedoutput NPN transistor (or switch) on the “on” state for the duration thetimer is set, which in this hypothetical case is 90 microseconds.Immediately after, which for a typical microcontroller may be 10nanoseconds, or 0.01 microseconds, the next address is asserted on theaddress bus 200, which in this hypothetical case is 00000010B=02H=02D. Adifferent address decoder recognizes this new address, which happens inthis case to be next to the previous pad, at the same z coordinate,which then causes its output to go high, which then starts the timerassociated with it, which then turns on the NPN transistor that turnsthe power on to pad 120_01_02, which will then stay on for the same 90microseconds. Microcontroller 1200 will similarly go through the list ofall pads in its memory, one by one, for example: 120_01_01, 120_01_02,120, 02_01, 120_02_02, 120_05_01, 120_05_02. Note that the 10nanoseconds it takes for microcontroller to move from one address to thenext in its list is so short a time when compared with the 90microseconds each pad is on, that it can be considered instantaneous.After the last pad is turned on, microcontroller 1200 will put on theaddress bus 200 a non-existing address, say 00000000B, so as no pad isset on until next cycle starts, which takes 5.55 milliseconds (f=180 Hz)from the beginning of the cycle, after which time a new cycle startsagain with the first address in the list, pad 120_01_01, which is00000001B, and so on. The result of the process is that every 5.55milliseconds (that is, at a frequency f=180 Hz) the full set of selectedpads is set at the correct voltage, injecting the current at theappropriate places for the desired duration of 90 microseconds.

Several necessary appurtenances to the microcontroller 1200 and currentcontroller 1230 (not shown) in box 1200 (not shown), and to the addressdecoder 830, timer/delay 820 and electronic switch 810 inside thepicafina are not mentioned because they are common elements known toprofessionals with current knowledge in the art of electronics. Forexample, there ought to exist a crystal controlled oscillator to keepthe time (that is why all computers wake-up with the correcttime-of-the-day+date); this and other known appurtenances are omitted inmy description of the device.

Referring to FIG. 13 c for a concrete case study, with the picafinapositioned by the surgeon as indicated, and remembering that the surgeonhas no means to position the picafina at the center of the region ofinterest, the stimulation pads number 1, 2, 3, 4 and 5 should beenergized, while pads 6 through 12 should be left un-energized orenergized at a lower voltage or current. This choice, in this case, isdictated by these pads being the ones that would cause an electricalcurrent to flow through the region of interest indicated, while causingnone or minimal current outside such region of interest. In practice themedical personnel does not know where the picafina is located withrespect to the region of interest, that is the person that is adjustingthe picafina for optimal performance, does not know what is displayed inFIG. 10 c. So this choice is not made based on the unknown position, butrather on observing good results, bad results or indifferent results.The choice is made by observing the existence of side effects, thatwould occur when energizing any of the pads 6 through 12, and alsoobserving the alleviation of the Parkinson Disease symptoms whenenergizing pads 1 through 5. In other words, the choice is made from theobservation of the effects, not from an a priori knowledge of thepositioning, as suggested by 13 c, which is only draw for purposes ofunderstanding the functioning. Also, depending on the size of the regionof interest, more or less layers of pads would be energized, all aboveand below said pads 1 through 5. Let us assume, for simplicity, thatonly two layers are to be energized in a picafina positioned asindicated in FIG. 13 c. The reader is reminded again that the actualposition is never known, as in 13 c, but rather the results ofstimulation are known, from which it is determined which pads toactivate. The following pads would be then energized: 01_1 through01_05, 02_01 through 02_05, etc.

It is better to describe the functioning of the picafina of my inventionby comparing it to the prior art. Prior art picafina is generally unableto avoid injecting current on the side of pads 6 to 12 in FIG. 13 c,this being a possible reason for the known side effects of DBS.

FIGS. 13 a and 13 b display two other possible relative relationsbetween the picafina inserted in a brain and a particular area ofinterest. The situation depicted in FIG. 13 a would cause understimulation, while the situation depicted in FIG. 13 b would causeover-stimulation with possible side effects. Neither is desirable. Apicafina which were able to adjust the voltage values at arbitrarypoints on its surface could ameliorate this situation.

DESCRIPTION AND OPERATION OF ALTERNATIVE EMBODIMENTS Second Embodimentof My Invention. Description of the Invention

Description of Second Embodiment—Short, Electrical Engineering Version.

A second embodiment discloses the use of multiple voltage (or current)wires (211) to set the stimulating electrical pads at different voltage(or current) values as needed, and a separate second binary address bus(201) to select which of said wires is connected to said stimulatingpads (110_xx_yy). Said second binary address bus (201) is separate fromthe first digital addressing system only logically, as each is anindependent set of wires running in parallel, with the same functionthough using separate wires each. It is also possible to use the sameset of wires then a separate switch to select what is being addressed,the pads or the current carrying wires. Each of the available wires 211to carry the stimulating signal can be connected to any of the availablestimulating pads 110, allowing several simultaneous different voltage(or current) settings, as many as there are stimulating wires 211. Inthis embodiment at the same time that a stimulating pad is selected, theoutput of its address decoder 830 besides opening (on) the electronicswitch associated with the pad that corresponds to itself, also enablesaid second address decoder 831 (or a demultiplexer) that selects one ofthe signal carrying wires 211 to connect the selected measuring pad toone of the available stimulating wires 211—the one selected by saidsecond address decoder 831 according to said second address bus 201 (seeFIG. 8 b). In FIG. 8 b many details are either omitted or else indicatedas a possible option that in any particular implementation may bedifferent to suit the particular electronics details. For example, theenable signal to said second address decoder 831, which in FIG. 8 b istaken as the output of said first address decoder 830, could be pulsestretched if needed to meet timing specifications of said second addressdecoder 831. Such details are obvious to the practitioners of the artand are not indicated in this patent description. It is intended thatthe number of connecting wires is much smaller than the number ofstimulating pads, or the order of 10s stimulating wires against an orderof several thousands stimulating pads, but this is not limiting to myinvention. Once the address for a particular connecting wire isselected, this address is latched, freeing both address buses to assertother addresses.

Description of Second Embodiment—Detailed Version.

The second embodiment of my invention uses two address buses, 200 toselect which stimulating pads is on, and 201 to select a particular wirewhich sets the voltage (or current) level. This alternative embodimentoffers the possibility of having several separate wires 211 connectingany stimulating pad 110 to one of a plurality of wires 211 settingdifferent voltage (or current) values. In this embodiment the number ofstimulating pads is still very large, say a few thousands, with asmaller number of connecting wires, say one to a few dozens or even lessthan a dozen. In this embodiment, after (or concomitantly) selecting aparticular stimulating pad 110 with decoder 830, say 120_10_01, the usersets another address in another independent address bus 201, which isdecoded by another address decoder 831 (FIGS. 8 a and 8 b), whichselects a particular connecting wire 211 to set the voltage (or current)at stimulating pad 120_10_01 to one of the possible values, each of saidpossible values being available at one of the voltage (or current) wires211. In this embodiment there is a holding memory (or latch) associatedwith address decoder 830 because the stimulating pad and the connectingwire have to stay selected even after the address buses 200 and 201 haveother address values for other combinations.

Consequently this second embodiment of my invention extends the use ofthe stimulating system to the selection of one connecting voltage (orcurrent) wire from a plurality of wires available throughout the body ofthe picafina, each one capable of connecting any of the stimulating padswith the proximal end of the picafina of my invention, from which theycan be extended by ordinary means to the power supply capable ofproducing a plurality of voltages (currents). FIG. 8 a shows theelectronic connections and parts. Stimulating pad 110 is connected via afirst digitally controlled switch 810, which turns on/off under thecontrol of a first address decoder 830, to said second address decoder831, which connects said stimulating pad 110 to one of the wires 211,each one set at a different voltage (or current) level. Once the addressbus selects an address for the voltage (current) wire 211_zz theselection is latched and stay latched until a signal is send to anotherwire, not shown, which has the appropriate circuitry to unlatch all thelatched addresses, which can be used to select new stimulating pads andnew connecting wires with a new selection cycle. The address bus thatselects an address for the stimulating pad 110_xx_yy has a timer/delaycircuit as in the main embodiment, which causes that the stimulationonce chosen stays on for a set time even after a new address is set onthe stimulating address bus.

Second Embodiment of My Invention. Operation of the Second Embodiment.

To operate the second embodiment the user must start resetting all thelatches to the off state, which he/she does with the latch off signal atwire_latch (not shown). He/she then starts selecting the first addressfor the stimulating pad with address decoder 830 he/she needs in thesame way as is done with the main embodiment, e.g., with individuallyset switches, or with a decoding pad, or with a microcomputer or anyequivalent way as known to the practitioners of the art, then, at thesame time (concomitantly) the user also selects the address for one ofthe available connecting wires 211_zz which run inside the length of thepicafina of my invention, which carries the voltage (current) thathe/she wants to use on said particular stimulating pad. Both addresses(200 and 201) have to be selected concomitantly because in this secondembodiment the address decoder 830 that selects a particular surfacemeasuring pad also enables said second address decoder 831 that selectswhich voltage (current) wire 211 is chosen, so that the power (voltageor current) wire is connected only to the selected stimulating pad. Withthis the user has completed the connection from the selected stimulatingpad to a single, identifiable wire at the proximal end of the picafinaof my invention. The user selects then a second stimulating pad 110 anda second connecting wire 211 in the same manner as the previous one,then a third and so on, until he/she selected all the desiredstimulating pads using one of the available power wires (voltage orcurrent) for each stimulating pad. Note that the voltages selected foreach stimulating pad 110 may or may not be different from each other—theoption is available if needed but inspection of the connectionsdescribed and indicated in the drawings will show that said pads can beall set at the same voltage (or current). When all the stimulating padsselections are made and the connecting wires 211 have been connected tothe external power source according to the desired voltage (or current)in each stimulating pad, the stimulating system is ready for a go signalto keep running as programmed by the medical practitioner. Severalvoltage (current) values can be used in parallel with this secondembodiment, for example, to stimulating areas of different sizes or ofdifferent impedances.

Third Embodiment of My Invention. Description of the Invention

Description of Second Embodiment—Short, Electrical Engineering Version.

A third embodiment of my invention is the extension of said secondembodiment using some of the power (voltage) wires as signal measuringwires. In this embodiment some of the wires 211 that set differentvoltages for said pads 110 are use as disclosed in said secondembodiment, connected to a battery or other voltage (or current) source,while some of said wires 211 are connected to a voltmeter or some othermeasuring instrument. In this third embodiment the picafina of myinvention is used not only to put a current on some neurons(stimulation) but to make measurements of the voltages at other neuronsas well. Typically these two functions are separate but there is noreason to be so other than the prior art impossibility to have enoughpads available for both. In this third embodiment said switch 810 isdesigned with an imput to latch its on-state (not shown), so as themeasurements can be continuously made once said switch 810 is selected.Instead of a latch on said switch 810 other possibilities exist, as knowto the practitioners of the art of electronics engineering.

Still another alternative embodiment of my invention is the use of radiosignals to create the addresses for the first address decoders (addressdecoders for the stimulating pads). In this embodiment there is nophysical first address wires connecting the distal end of the picafinawith the user (researcher or neurologist). Any radio communication linkis feasible, over the EM spectrum, including, e.g., radio waves of allfrequencies and wavelengths, microwaves, infrared, visible, ultravioletetc., and such action-at-a-distance information is sometimes referred toas telemetry. This invention does not include a new radio communicationsystem, but simply use existing telemetry devices. In this alternativeembodiment the connecting wires for the first address bus 200 aresubstituted by a telemetry unit inside the picafina of my invention,which receives the addresses sent by the user using a transmitting unit.Once received, the addresses are stored in memory physically located atthe distal end of the picafina, near the measuring tips, said storingmemory taking the place of the connecting wires. Such an alternativeembodiment decreases the number of wires connecting the picafina withthe outside world, which may be important when taking measurements onsmall animals, as in a mouse or even on an insect, when it may beadvantageous to use smaller wires connecting the animal to thecontrolling and measuring instruments.

Still another alternative embodiment of my invention is the use of radiosignals to create the addresses for the second address decoders (addressdecoders for the power wires—voltage or current). In this embodimentthere is no physical second address wires connecting the distal end ofthe picafina with the user (researcher or neurologist). Any radiocommunication link is feasible, over the EM spectrum, including, e.g.,radio waves of all frequencies and wavelengths, microwaves, infrared,visible, ultraviolet etc., and such action-at-a-distance information issometimes referred to as telemetry. This invention does not include anew radio communication system, but simply use existing telemetrydevices. In this alternative embodiment the connecting wires for theaddress bus 201 are substituted by a telemetry unit inside the picafinaof my invention, which receives the addresses sent by the user using atransmitting unit. Once received, the addresses are stored in memoryphysically located at the distal end of the picafina, near the measuringtips, said storing memory taking the place of the connecting wires. Suchan alternative embodiment decreases the number of wires connecting thepicafina with the outside world, which may be important when takingmeasurements on small animals, as in a mouse or even on an insect, whenit may be advantageous to use smaller wires connecting the animal to thecontrolling and measuring instruments.

Still another alternative embodiment of my invention is the use of radiosignals to create the addresses for both the first and the secondaddress decoders (address decoders for the stimulating pads and addressdecoders for the power wires—voltage or current). In this embodimentthere is no physical first and second address wires connecting thedistal end of the picafina with the user (researcher or neurologist),both advantages mentioned on the two paragraphs above being attainedsimultaneously.

CONCLUSION, RAMIFICATIONS, AND SCOPE OF INVENTION

It ought to be obvious to people skilled in the art that far moreindependent stimulating pads or contacts are possible to address in theform disclosed in the main embodiment, which is presented with 12 padsper ring and 16 rings, only to make it easier to follow the drawings andexplanation.

The connections inside said picafina are made with any of thetechnologies developed for printed circuits and/or chip manufacture(integrated circuits or IC). For example, both the subtractive and theadditive processes used in printed circuit manufacture can be used toprint the connecting power and address lines. The integrated circuitsand transistors shown, for example, at FIG. 7 could be made with theordinary technology used for chip manufacture, as well as some of thewires that interconnect them and/or wires that connect them with themain connecting wires along the picafina. It is also possible to use acombination of these, some connections using the printed circuittechnology, other using the smaller IC technology, the particular choicedepending on the size and complexity of the particular picafina.

Thus the reader will see that the electrode pads of the inventionprovide a highly reliable device which offers the advantage over priorart of being able to deliver electrical pulses on more precisely locatedpoints on the vicinity of neurons, nerves and other cells inside livingorganisms than prior art does. The smaller dimensions of the deliveringelectrodes (pads) of my invention allow for more precise delivery ofcurrent to a single neuron, if so desired, instead of averagedistributed shotguns to very many neurons that happen to be near alarger delivering probes of prior art. At the same time my inventionpermits the delivery of electrical pulses from many pads in parallel,which pads can be adjoining to each other, making the equivalent of alarger pad of prior art, or from spatially separated pads, allowing fornew and unexpected results. These options give more flexibility andoptions to the user of my invention. Moreover, the electrode pads of myinvention allow for changing the position of pulse delivery from pointsseparated by a few micrometers, or the distance between each pad,without moving the supporting structure (the picafina). This possibilityof changing the delivery pad to be used while keeping the picafina of myinvention in the same place is important, as each repositioning involvestrauma to the animal. Moreover, the change from one pad to the other isalso important, because the distance between the pads can be made verysmall, a few micrometers with modern technology of semiconductor andprinted circuit board (PCB) manufacture, which is much smaller than theseparation between pads in multi pad stimulating devices in used todayby current art. Though the picafina cannot be positioned with anyaccuracy with respect to any neuron or other body cell, the possibilityof adjustments of the delivery position, switching from one pad toanother nearby pad is equivalent to micropositioning the delivery site,or to make small changes on the pulse delivery site.

Another improvement is in making neural stimulations that advancespatially on time along the neurons, which can be achieved by turningthe small pads on as a progressive wave that passes by, turning off thepads behind, as the letters on announcement displays that moves theletters, or as the lighted pointing arrows ordering lane changes onhighways at construction sites, a possibility that can potentially openthe possibility of a less intrusive neural stimulation (not as muchcurrent, not as much electrical power), also more localized in area(that is, volume), sparing unnecessary neurons from being stimulated.

The wires at the proximal end of the picafina of my invention do nothave to be grouped as indicated in the main embodiment, any othergrouping being acceptable, as the grouping does not alter the working ofmy invention. For example, all the wires could end on a singleconnector, or each wire could have its own dedicated connector, or anycombination of these, because the particular form of connecting thewires are not part of this invention.

The wires or cables at the proximal end of the picafina of my inventionmay be duplicated (redundant wires), as shown at FIG. 12, so that thepicafina of my invention can still be used if one of the wires happensto break, simply changing to its backup wire or cable.

The pulse delivery pads can be of any shape different of the circularshape indicated in the main embodiment without altering the scope of theinvention. For example, the delivery pads can be square shaped, asindicated in FIG. 2, or they can be elongated, as shown at FIG. 3, orthey can be in the shapes shown at FIGS. 5 a and 5 b. These variationsand many others are possible and fit particular applications, none ofthem expressing any intrinsic variation from my invention.

The very body of the picafina of my invention can have shapes other thancylindrical. FIGS. 6 a and 6 b show two such possible variations.Variations on the shape of the picafina of my invention to adapt tospecific applications do not constitute an intrinsic variation of myinvention and are covered by this patent.

The distal interior part of the picafina described in the mainembodiment is solid and made of the same material as its surface, butthis is not necessary, it being possible to have a hollow interior, oran interior made of a different material then the exterior surface, thisdetail not affecting the working of the invention as it will be seen bythe persons familiar with the art.

The address decoders 830 that turn on/off the switches 810, therebyconnecting the pulse delivering pads 110 can be as simple as a digital(or binary) comparator, for example the National Instruments 54AC520 orthe Texas Instruments 5962-8681801RA, or some other more complexcircuit, or even a especially designed electronic circuit, theparticular nature of the address decoder not impacting my invention, butonly that it recognizes that the address asserted in the address bus 200is the same as the address assigned to the contact that it is supposedto turn on/off.

While my above description contains many specificities, these should notbe construed as limitations on the scope of the invention, but rather asan exemplification of one preferred embodiment thereof and a few typicalvariations. Many other variations are possible. For example the crosssection of the picafina of my invention can be of many other shape, aselliptical or rectangular. Besides elliptical and rectangular, it can beof any irregular shape, or the cross section can even vary along thelong dimension of the picafina. The pulse delivering pads do not have tobe flush with the picafina's body, but can be either protruding out ofit or be recessed onto it. The dimensions suggested for the mainembodiment are intended for a picafina designed to deliver electricalpulses deep in the brain of a human animal; these dimensions arenecessarily different when the intended animal is not a Homo, as asmaller mouse or an even much smaller insect, or for stimulation at thebrain cortex, for example, which is located just below the skull, or forstimulation on the spinal cord, or from other neurons or other cells onthe heart, intestines, or any other organs or extremities like arms. Thestimulating pads can be made of metals other than titanium, such asplatinum, vanadium, iridium, silver, gold, surgical steel, stainlesssteel, MP35N, platinum-iridium, amalgams, alloys, and combinations,among others. and the body can be made of other insulators other thansilicone, such as polyurethane, polyethylene, polyimide,polyvinylchloride, PTFE, ETFE, ceramics, various biocompatible polymers,or combinations of these, among others.

The connections inside said picafina are made with any of thetechnologies developed for printed circuits and/or chip manufacture(integrated circuits or IC). For example, both the subtractive and theadditive processes used in printed circuit manufacture can be used toprint the connecting power, ground and address lines. The integratedcircuits and transistors shown schematically, for example, at FIGS. 7 aand 7 b, could be made with the ordinary technology used for chipmanufacture, as well as some of the wires that interconnect them and/orwires that connect them with the main connecting wires along thepicafina. It is also possible to use a combination of these, someconnections using the printed circuit technology, other using thesmaller IC technology, the particular choice depending on the size andcomplexity of the particular picafina.

Accordingly, the scope of the invention should be determined not by theembodiment(s) illustrated, but by the appended claims, drawings andinvention description, and their legal equivalents, including obviousextentions and variations of it as seen by persons with normal skills inthe art.

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1. A device for electrically stimulating cells, comprising: an electricenergy storage at a first position, and a control electronics at asecond position or at the first position; a wireless action at adistance electronic device capable of transmitting and receivinginformation at a distance, the action at a distance electronic devicehaving an electronic addressing means and/or an electronic digitalcontrol electronic means capable of transmitting and/or receivingelectronic address bits and/or electronic control bits using a wirelessaction at a distance device; a picafina device body with a proximalextremity, a distal extremity, an inner lumen and an outer surface; aplurality of stimulating electrodes on the outer surface of the picafinain fixed relative positions at the distal extremity; a plurality offirst on/off switches, each of the first on/off switches associated withone of the stimulating electrodes for selecting the associatedstimulating electrode; a first plurality of wires running inside thelumen of the picafina with a proximal extremity and a distal extremity;a second plurality of wires running outside the picafina with a proximalextremity and a distal extremity; wherein the first plurality of wireshave wires comprising a group of electric power wires, each electricpower wire at a different voltage level or at the same voltage level orat a different current level or at the same current level, the firstplurality of wires being connected to the stimulating electrodes via theplurality of first plurality of on/off switches at their distalextremity and to the second plurality of wires at their proximalextremity; a plurality of second on/off switches, each of the secondon/off switches associated with one of the wires belonging to the firstplurality of wires running inside the lumen; the second plurality ofwires running outside the picafina device body configured to connect thefirst plurality of wires to the electric energy storage; the electronicaddressing means having sufficient bits to form a first address touniquely identify each of the stimulating electrodes and to form asecond address to uniquely identify each of the wires from the firstplurality of wires; a plurality of first address decoders, wherein eachof the first address decoders having a first unique digital address iscapable of selecting the state of one of the first on/off switchesaccording to the first address from the electronic addressing means; aplurality of second address decoders, wherein each of the second addressdecoders having a second unique digital address is capable of selectingthe state of the second on/off switches according to the second addressfrom the electronic addressing means; wherein the first address assertedon the electronic addressing means and conveyed to the first addressdecoders at the picafina is compared to the first unique digitaladdresses of the first address decoders and when the respective firstunique address of one of the first address decoders is equal to thefirst address asserted on the electronic addressing means, that firstaddress decoder causes the associated first on/off switch to enter the“on” state to select the associated stimulating electrodes, and thesecond address asserted on the addressing means at the controlelectronics and conveyed to the second address decoders at the picafinais compared to the second unique digital addresses of the second addressdecoders, and when the respective second unique address of one of thesecond address decoders is equal to the second address asserted on theelectronic addressing means, that second address decoder causes theassociated second on/off switch to enter the “on” state to select theassociated one of the wires from the first plurality of wires, therebycreating a completed electrical connection between the selectedstimulating electrode and the selected one of the wires from the firstplurality of wires; wherein the stimulating electrodes are configured toapply a stimulating electric energy to the cells in the vicinity of thestimulating electrode.
 2. The device of claim 1 further comprising aplurality of measuring electrodes at the surface of the picafina devicebody, a measuring device capable of measuring an electric potentialand/or an electric current, and electrical means to connect themeasuring electrodes to the measuring device.
 3. The device of claim 2further comprising a plurality of electrical amplifiers, each electricalamplifier between each one of the measuring electrodes and the measuringdevice.
 4. The device of claim 2 further comprising a means forconnecting in parallel a subset of the plurality of the stimulatingelectrodes or a subset of the plurality of the measuring electrodes toone of the wires from the first plurality of wires, the means capable oflatching the on state of each of the first on/off switches, wherein thesubset of the plurality of the stimulating electrodes or the subset ofthe plurality of the measuring electrodes act together as a largersurface measuring electrode.
 5. The device of claim 1 further comprisinga plurality of latching/unlatching circuits, each one of thelatching/unlatching circuits being capable of being latched and/orunlatched by a circuit activated by a command carried by the controlelectronics means over the wireless action at a distance means device,each one of the latching and/or unlatching circuits associated with oneof the first on/off switches and with one of the second on/off switches,the plurality of latching/unlatching circuits configured for keeping thecompleted electrical connection made by the first on/off switches andthe second on/off switches for an indefinite amount of time untilunlatched by the latching/unlatching circuit.
 6. The device of claim 2wherein the second plurality of wires connects the first plurality ofwires to the electric energy storage, and the electric energy storage isa variable level electric energy storage configured to apply variablelevels of electric potentials and/or variable levels of currents toselected stimulating electrodes according to their unique digitaladdresses, via the second plurality of wires and the first plurality ofwires, wherein the selected measuring and/or stimulating electrodes actas source of electrical stimulation and/or electrical measurements tothe cells around the selected_measuring and/or stimulating electrodes.7. A device for measuring an electrical signal occurring in cells and/orfor stimulating cells, comprising: a measuring and/or recordinginstrument, an electric energy storage, and a control electronics; apicafina device body with a proximal extremity, a distal extremity, aninner lumen and an outer surface; a plurality of measuring and/orstimulating electrodes on the outer surface of the picafina in fixedrelative positions at the distal extremity; a plurality of first on/offswitches, each of the first on/off switches associated with one of themeasuring and/or stimulating electrodes for selecting the associatedmeasuring and/or stimulating electrodes; a first plurality of wiresrunning inside the lumen and having a proximal extremity and a distalextremity; a second plurality of wires running outside the picafina;wherein the first plurality of wires have wires comprising a group ofelectric power wires, each electric power wire at a different voltagelevel and/or a group consisting of wires to carry a measured voltagelevel from one of the measuring and/or stimulating electrodes, the firstplurality of wires being connected to the measuring and/or stimulatingelectrodes via the plurality of first on/off switches at their distalextremity and to the second plurality of wires on their proximalextremity; a plurality of second on/off switches, each of the secondon/off switches associated with one of the wires belonging to the firstplurality of wires running inside the lumen; the second plurality ofwires running outside the picafina device body configured to connect thefirst plurality of wires to at least one element of the group consistingof: the measuring and/or recording instrument, the electric energystorage, and the control electronics; a timer electronic circuit thatcontrols the duration of the “on” time of the first on/off switches andthe “on” time of the second on/off switches, such that once one of theplurality of the first or second on/off switches is turned “on” it iskept in the “on” state for a predetermined time, after which the timerelectronic circuit moves the switch to the “off” state. wherein themeasuring and/or stimulating electrodes are configured to measure theelectrical signal values at the body cells next to the respectivemeasuring and/or stimulating electrodes and/or to apply a stimulatingelectric current to the cells in the vicinity of the measuring and/orstimulating electrodes.
 8. The device of claim 7 further comprising aplurality of electrical amplifiers, each electrical amplifier betweeneach one of the measuring and/or stimulating electrodes and theassociated first on/off switch.
 9. The device of claim 7 furthercomprising a means for connecting in parallel a subset of the pluralityof the measuring and/or stimulating electrodes to one of the wires fromthe first plurality of wires, the means capable of latching the on stateof each of the first on/off switches, wherein the subset of theplurality of the measuring and/or stimulating electrodes act together asa larger surface measuring electrode.
 10. The device of claim 7 whereinthe second plurality of wires connects the first plurality of wires tothe electric energy storage, and the electric energy storage is avariable level electric energy storage configured to apply variablelevels of electric potentials and/or currents to selected measuringand/or stimulating electrodes according to their digital addresses,wherein the selected measuring and/or stimulating electrodes act assource of electrical stimulation to the cells around the selectedmeasuring and/or stimulating electrodes.